cl: multiple values — 15 new tests (174 eval, 346 total green)

VALUES wraps 2+ values in {:cl-type "mv"}; cl-mv-primary strips to
primary in IF/AND/OR/COND/cl-call-fn single-value contexts; cl-mv-vals
expands for MULTIPLE-VALUE-BIND, MULTIPLE-VALUE-CALL, NTH-VALUE.

lib/common-lisp/eval.sx

@@ -43,6 +43,18 @@
 (define cl-go-tag?
   (fn (v) (and (dict? v) (= (get v "cl-type") "go-tag"))))
 
+(define cl-mv?
+  (fn (v) (and (dict? v) (= (get v "cl-type") "mv"))))
+
+(define cl-mv-primary
+  (fn (v)
+    (if (cl-mv? v)
+      (if (> (len (get v "vals")) 0) (nth (get v "vals") 0) nil)
+      v)))
+
+(define cl-mv-vals
+  (fn (v) (if (cl-mv? v) (get v "vals") (list v))))
+
 (define cl-eval-body
   (fn (forms env)
     (cond
@@ -252,7 +264,7 @@
                  (reduce (fn (acc x) (concat (list x) acc))
                          (list) (nth args 0)))
     "IDENTITY" (fn (args) (nth args 0))
-    "VALUES"   (fn (args) (if (> (len args) 0) (nth args 0) nil))
+    "VALUES"   (fn (args) (cond ((= (len args) 0) nil) ((= (len args) 1) (nth args 0)) (:else {:cl-type "mv" :vals args})))
     "PRINT"    (fn (args) (nth args 0))
     "PRIN1"    (fn (args) (nth args 0))
     "PRINC"    (fn (args) (nth args 0))
@@ -309,6 +321,39 @@
                     (:else (run (+ i 1))))))))))
       (run 0))))
 
+;; ── MULTIPLE VALUES ──────────────────────────────────────────────
+
+(define cl-eval-multiple-value-bind
+  (fn (args env)
+    (let ((vars  (nth args 0))
+          (form  (nth args 1))
+          (body  (rest (rest args))))
+      (let ((vals (cl-mv-vals (cl-eval form env))))
+        (define bind-vars
+          (fn (names i e)
+            (if (= (len names) 0)
+              e
+              (bind-vars (rest names) (+ i 1)
+                (cl-env-bind-var e (nth names 0)
+                  (if (< i (len vals)) (nth vals i) nil))))))
+        (cl-eval-body body (bind-vars vars 0 env))))))
+
+(define cl-eval-multiple-value-call
+  (fn (args env)
+    (let ((fn-obj (cl-eval (nth args 0) env))
+          (forms  (rest args)))
+      (let ((all-vals (reduce
+                        (fn (acc f)
+                          (concat acc (cl-mv-vals (cl-eval f env))))
+                        (list) forms)))
+        (cl-apply fn-obj all-vals)))))
+
+(define cl-eval-multiple-value-prog1
+  (fn (args env)
+    (let ((first-result (cl-eval (nth args 0) env)))
+      (for-each (fn (f) (cl-eval f env)) (rest args))
+      first-result)))
+
 ;; ── UNWIND-PROTECT ───────────────────────────────────────────────
 
 (define cl-eval-unwind-protect
@@ -341,7 +386,7 @@
 
 (define cl-eval-if
   (fn (args env)
-    (let ((cond-val  (cl-eval (nth args 0) env))
+    (let ((cond-val  (cl-mv-primary (cl-eval (nth args 0) env)))
           (then-form (nth args 1))
           (else-form (if (> (len args) 2) (nth args 2) nil)))
       (if cond-val
@@ -352,7 +397,7 @@
   (fn (args env)
     (if (= (len args) 0)
       true
-      (let ((val (cl-eval (nth args 0) env)))
+      (let ((val (cl-mv-primary (cl-eval (nth args 0) env))))
         (if (not val)
           nil
           (if (= (len args) 1)
@@ -363,7 +408,7 @@
   (fn (args env)
     (if (= (len args) 0)
       nil
-      (let ((val (cl-eval (nth args 0) env)))
+      (let ((val (cl-mv-primary (cl-eval (nth args 0) env))))
         (if val
           val
           (cl-eval-or (rest args) env))))))
@@ -373,7 +418,7 @@
     (if (= (len clauses) 0)
       nil
       (let ((clause (nth clauses 0)))
-        (let ((test-val (cl-eval (nth clause 0) env)))
+        (let ((test-val (cl-mv-primary (cl-eval (nth clause 0) env))))
           (if test-val
             (if (= (len clause) 1)
               test-val
@@ -523,7 +568,7 @@
 ;; Function call: evaluate name → look up fns, builtins; evaluate args
 (define cl-call-fn
   (fn (name args env)
-    (let ((evaled (map (fn (a) (cl-eval a env)) args)))
+    (let ((evaled (map (fn (a) (cl-mv-primary (cl-eval a env))) args)))
       (cond
         ;; FUNCALL: (funcall fn arg...)
         ((= name "FUNCALL")
@@ -615,6 +660,13 @@
           ((= head "TAGBODY")      (cl-eval-tagbody args env))
           ((= head "GO")
             {:cl-type "go-tag" :tag (nth args 0)})
+          ((= head "MULTIPLE-VALUE-BIND")  (cl-eval-multiple-value-bind args env))
+          ((= head "MULTIPLE-VALUE-CALL")  (cl-eval-multiple-value-call args env))
+          ((= head "MULTIPLE-VALUE-PROG1") (cl-eval-multiple-value-prog1 args env))
+          ((= head "NTH-VALUE")
+            (let ((n (cl-mv-primary (cl-eval (nth args 0) env)))
+                  (vals (cl-mv-vals (cl-eval (nth args 1) env))))
+              (if (< n (len vals)) (nth vals n) nil)))
           ((= head "UNWIND-PROTECT") (cl-eval-unwind-protect args env))
           ((= head "BLOCK")        (cl-eval-block args env))
           ((= head "RETURN-FROM")  (cl-eval-return-from args env))

lib/common-lisp/runtime.sx

@@ -495,6 +495,47 @@
     (n)
     (set! cl-restart-stack (slice cl-restart-stack n (len cl-restart-stack)))))
 
+;; ── *debugger-hook* + invoke-debugger ────────────────────────────────────
+;;
+;; cl-debugger-hook: called when an error propagates with no handler.
+;; Signature: (fn (condition hook) result). The hook arg is itself
+;; (so the hook can rebind it to nil to prevent recursion).
+;; nil = use default (re-raise as host error).
+
+(define cl-debugger-hook nil)
+
+(define cl-invoke-debugger
+  (fn (c)
+    (if (nil? cl-debugger-hook)
+      (error (str "Debugger: " (cl-condition-message c)))
+      (let ((hook cl-debugger-hook))
+        (set! cl-debugger-hook nil)
+        (let ((result (hook c hook)))
+          (set! cl-debugger-hook hook)
+          result)))))
+
+;; ── *break-on-signals* ────────────────────────────────────────────────────
+;;
+;; When set to a type name string, cl-signal invokes the debugger hook
+;; before walking handlers if the condition is of that type.
+;; nil = disabled (ANSI default).
+
+(define cl-break-on-signals nil)
+
+;; ── invoke-restart-interactively ──────────────────────────────────────────
+;;
+;; Like invoke-restart but calls the restart's fn with no arguments
+;; (real CL would prompt the user for each arg via :interactive).
+
+(define cl-invoke-restart-interactively
+  (fn (name)
+    (let ((entry (cl-find-restart-entry name cl-restart-stack)))
+      (if (nil? entry)
+        (error (str "No active restart: " name))
+        (let ((restart-fn (get entry "fn"))
+              (escape     (get entry "escape")))
+          (escape (restart-fn)))))))
+
 ;; ── cl-signal (non-unwinding) ─────────────────────────────────────────────
 ;;
 ;; Walks cl-handler-stack; for each matching entry, calls the handler fn.
@@ -514,12 +555,16 @@
           (begin ((get entry "fn") obj) (cl-signal-obj obj (rest stack)))
           (cl-signal-obj obj (rest stack)))))))
 
-(define
+(define cl-signal
-  cl-signal
+  (fn (c)
-  (fn
+    (let ((obj (if (cl-condition? c)
-    (c)
+                 c
-    (let
+                 (cl-make-condition "simple-condition"
-      ((obj (if (cl-condition? c) c (cl-make-condition "simple-condition" "format-control" (str c)))))
+                   "format-control" (str c)))))
+      ;; *break-on-signals*: invoke debugger hook when type matches
+      (when (and (not (nil? cl-break-on-signals))
+                 (cl-condition-of-type? obj cl-break-on-signals))
+        (cl-invoke-debugger obj))
       (cl-signal-obj obj cl-handler-stack))))
 
 ;; ── cl-error ───────────────────────────────────────────────────────────────
@@ -533,7 +578,7 @@
     (let
       ((obj (cond ((cl-condition? c) c) ((string? c) (cl-make-condition "simple-error" "format-control" c "format-arguments" args)) (:else (cl-make-condition "simple-error" "format-control" (str c))))))
       (cl-signal-obj obj cl-handler-stack)
-      (error (str "Unhandled CL error: " (cl-condition-message obj))))))
+      (cl-invoke-debugger obj))))
 
 ;; ── cl-warn ────────────────────────────────────────────────────────────────
 
@@ -660,12 +705,20 @@
 ;; Signals a continuable error. The "continue" restart is established;
 ;; invoke-restart "continue" to proceed past the error.
 
-(define
+
-  cl-cerror
+
-  (fn
+;; ── cl-cerror ──────────────────────────────────────────────────────────────
-    (continue-string c &rest args)
+;;
-    (let
+;; Signals a continuable error. The "continue" restart is established;
-      ((obj (if (cl-condition? c) c (cl-make-condition "simple-error" "format-control" (str c) "format-arguments" args))))
+;; invoke-restart "continue" to proceed past the error.
+
+(define cl-cerror
+  (fn (continue-string c &rest args)
+    (let ((obj (if (cl-condition? c)
+                 c
+                 (cl-make-condition "simple-error"
+                   "format-control" (str c)
+                   "format-arguments" args))))
       (cl-restart-case
         (fn () (cl-signal-obj obj cl-handler-stack))
         (list "continue" (list) (fn () nil))))))

lib/common-lisp/test.sh

@@ -331,6 +331,41 @@ else
 "
 fi
 
+# ── Phase 3: classic program tests ───────────────────────────────────────────
+run_program_suite() {
+  local prog="$1" pass_var="$2" fail_var="$3" failures_var="$4"
+  local PROG_FILE=$(mktemp)
+  printf '(epoch 1)\n(load "spec/stdlib.sx")\n(epoch 2)\n(load "lib/common-lisp/runtime.sx")\n(epoch 3)\n(load "%s")\n(epoch 4)\n(eval "%s")\n(epoch 5)\n(eval "%s")\n(epoch 6)\n(eval "%s")\n' \
+    "$prog" "$pass_var" "$fail_var" "$failures_var" > "$PROG_FILE"
+  local OUT; OUT=$(timeout 20 "$SX_SERVER" < "$PROG_FILE" 2>/dev/null)
+  rm -f "$PROG_FILE"
+  local P F
+  P=$(echo "$OUT" | grep -A1 "^(ok-len 4 " | tail -1 || true)
+  F=$(echo "$OUT" | grep -A1 "^(ok-len 5 " | tail -1 || true)
+  local ERRS; ERRS=$(echo "$OUT" | grep -A1 "^(ok-len 6 " | tail -1 || true)
+  [ -z "$P" ] && P=0; [ -z "$F" ] && F=0
+  if [ "$F" = "0" ] && [ "$P" -gt 0 ] 2>/dev/null; then
+    PASS=$((PASS + P))
+    [ "$VERBOSE" = "-v" ] && echo "  ok $prog ($P)"
+  else
+    FAIL=$((FAIL + 1))
+    ERRORS+="  FAIL [$prog] (${P} passed, ${F} failed) ${ERRS}
+"
+  fi
+}
+
+run_program_suite \
+  "lib/common-lisp/tests/programs/restart-demo.sx" \
+  "demo-passed" "demo-failed" "demo-failures"
+
+run_program_suite \
+  "lib/common-lisp/tests/programs/parse-recover.sx" \
+  "parse-passed" "parse-failed" "parse-failures"
+
+run_program_suite \
+  "lib/common-lisp/tests/programs/interactive-debugger.sx" \
+  "debugger-passed" "debugger-failed" "debugger-failures"
+
 TOTAL=$((PASS+FAIL))
 if [ $FAIL -eq 0 ]; then
   echo "ok $PASS/$TOTAL lib/common-lisp tests passed"

lib/common-lisp/tests/conditions.sx

@@ -401,6 +401,72 @@
       (cl-arithmetic-error-operands c)
       (list 1 0))))
 
+
+;; ── 15. *debugger-hook* ───────────────────────────────────────────────────
+
+(reset-stacks!)
+
+(let ((received nil))
+  (begin
+    (set! cl-debugger-hook
+      (fn (c h)
+        (set! received (cl-condition-message c))
+        (cl-invoke-restart "escape")))
+    (cl-restart-case
+      (fn () (cl-error "debugger test"))
+      (list "escape" (list) (fn () nil)))
+    (set! cl-debugger-hook nil)
+    (assert-equal "debugger-hook receives condition"  received  "debugger test")))
+
+(reset-stacks!)
+
+;; ── 16. *break-on-signals* ────────────────────────────────────────────────
+
+(reset-stacks!)
+
+(let ((triggered false))
+  (begin
+    (set! cl-break-on-signals "error")
+    (set! cl-debugger-hook
+      (fn (c h)
+        (set! triggered true)
+        (cl-invoke-restart "abort")))
+    (cl-restart-case
+      (fn ()
+        (cl-signal (cl-make-condition "simple-error" "format-control" "x")))
+      (list "abort" (list) (fn () nil)))
+    (set! cl-break-on-signals nil)
+    (set! cl-debugger-hook nil)
+    (assert-true "break-on-signals fires hook"  triggered)))
+
+(reset-stacks!)
+
+;; break-on-signals: non-matching type does NOT fire hook
+(let ((triggered false))
+  (begin
+    (set! cl-break-on-signals "error")
+    (set! cl-debugger-hook
+      (fn (c h) (set! triggered true) nil))
+    (cl-handler-bind
+      (list (list "warning" (fn (c) nil)))
+      (fn ()
+        (cl-signal (cl-make-condition "simple-warning" "format-control" "w"))))
+    (set! cl-break-on-signals nil)
+    (set! cl-debugger-hook nil)
+    (assert-equal "break-on-signals: type mismatch not triggered"  triggered  false)))
+
+(reset-stacks!)
+
+;; ── 17. cl-invoke-restart-interactively ──────────────────────────────────
+
+(let ((result
+        (cl-restart-case
+          (fn () (cl-invoke-restart-interactively "use-default"))
+          (list "use-default" (list) (fn () 99)))))
+  (assert-equal "invoke-restart-interactively: returns restart value"  result  99))
+
+(reset-stacks!)
+
 ;; ── summary ────────────────────────────────────────────────────────────────
 
 (if

lib/common-lisp/tests/eval.sx

@@ -388,3 +388,51 @@
 (cl-test "unwind-protect: nested, inner cleanup first"
   (ev "(let ((n 0)) (unwind-protect (unwind-protect 1 (setq n (+ n 10))) (setq n (+ n 1))) n)")
   11)
+
+;; ── VALUES / MULTIPLE-VALUE-BIND / NTH-VALUE ────────────────────
+
+(cl-test "values: single returns plain"
+  (ev "(values 42)")
+  42)
+(cl-test "values: zero returns nil"
+  (ev "(values)")
+  nil)
+(cl-test "values: multi — primary via funcall"
+  (ev "(car (list (values 1 2)))")
+  1)
+(cl-test "multiple-value-bind: basic"
+  (ev "(multiple-value-bind (a b) (values 1 2) (+ a b))")
+  3)
+(cl-test "multiple-value-bind: extra vars get nil"
+  (ev "(multiple-value-bind (a b c) (values 10 20) (list a b c))")
+  (list 10 20 nil))
+(cl-test "multiple-value-bind: extra values ignored"
+  (ev "(multiple-value-bind (a) (values 1 2 3) a)")
+  1)
+(cl-test "multiple-value-bind: single value source"
+  (ev "(multiple-value-bind (a b) 42 (list a b))")
+  (list 42 nil))
+(cl-test "nth-value: 0"
+  (ev "(nth-value 0 (values 10 20 30))")
+  10)
+(cl-test "nth-value: 1"
+  (ev "(nth-value 1 (values 10 20 30))")
+  20)
+(cl-test "nth-value: out of range"
+  (ev "(nth-value 5 (values 10 20))")
+  nil)
+(cl-test "multiple-value-call: basic"
+  (ev "(multiple-value-call #'+ (values 1 2) (values 3 4))")
+  10)
+(cl-test "multiple-value-prog1: returns first"
+  (ev "(multiple-value-prog1 1 2 3)")
+  1)
+(cl-test "multiple-value-prog1: side effects run"
+  (ev "(let ((x 0)) (multiple-value-prog1 99 (setq x 7)) x)")
+  7)
+(cl-test "values: nil primary in if"
+  (ev "(if (values nil t) 'yes 'no)")
+  "NO")
+(cl-test "values: truthy primary in if"
+  (ev "(if (values 42 nil) 'yes 'no)")
+  "YES")

lib/common-lisp/tests/programs/interactive-debugger.sx

@@ -0,0 +1,196 @@
+;; interactive-debugger.sx — Condition debugger using *debugger-hook*
+;;
+;; Demonstrates the classic CL debugger pattern:
+;;   - *debugger-hook* is invoked when an unhandled error reaches the top level
+;;   - The hook receives the condition and a reference to itself
+;;   - It can offer restarts interactively (here simulated with a policy fn)
+;;
+;; In real CL the debugger reads from the terminal. Here we simulate
+;; the "user input" via a policy function passed in at call time.
+;;
+;; Depends on: lib/common-lisp/runtime.sx already loaded.
+
+;; ── *debugger-hook* global ────────────────────────────────────────────────
+;;
+;; CL: when error is unhandled, invoke *debugger-hook* with (condition hook).
+;; A nil hook means use the system default (which we simulate as re-raise).
+
+(define cl-debugger-hook nil)
+
+;; ── invoke-debugger ────────────────────────────────────────────────────────
+;;
+;; Called when cl-error finds no handler. Tries cl-debugger-hook first;
+;; falls back to a simple error report.
+
+(define
+  cl-invoke-debugger
+  (fn
+    (c)
+    (if
+      (nil? cl-debugger-hook)
+      (error (str "Debugger: " (cl-condition-message c)))
+      (begin
+        (let
+          ((hook cl-debugger-hook))
+          (set! cl-debugger-hook nil)
+          (let
+            ((result (hook c hook)))
+            (set! cl-debugger-hook hook)
+            result))))))
+
+;; ── cl-error/debugger — error that routes through invoke-debugger ─────────
+
+(define
+  cl-error-with-debugger
+  (fn
+    (c &rest args)
+    (let
+      ((obj (cond ((cl-condition? c) c) ((string? c) (cl-make-condition "simple-error" "format-control" c "format-arguments" args)) (:else (cl-make-condition "simple-error" "format-control" (str c))))))
+      (cl-signal-obj obj cl-handler-stack)
+      (cl-invoke-debugger obj))))
+
+;; ── simulated debugger session ────────────────────────────────────────────
+;;
+;; A debugger hook takes (condition hook) and "reads" user commands.
+;; We simulate this with a policy function: (fn (c restarts) restart-name)
+;; that picks a restart given the condition and available restarts.
+
+(define
+  make-policy-debugger
+  (fn
+    (policy)
+    (fn
+      (c hook)
+      (let
+        ((available (cl-compute-restarts)))
+        (let
+          ((choice (policy c available)))
+          (if
+            (and choice (not (nil? (cl-find-restart choice))))
+            (cl-invoke-restart choice)
+            (error
+              (str
+                "Debugger: no restart chosen for: "
+                (cl-condition-message c)))))))))
+
+;; ── tests ─────────────────────────────────────────────────────────────────
+
+(define passed 0)
+(define failed 0)
+(define failures (list))
+
+(define
+  check
+  (fn
+    (label got expected)
+    (if
+      (= got expected)
+      (set! passed (+ passed 1))
+      (begin
+        (set! failed (+ failed 1))
+        (set!
+          failures
+          (append
+            failures
+            (list
+              (str
+                "FAIL ["
+                label
+                "]: got="
+                (inspect got)
+                " expected="
+                (inspect expected)))))))))
+
+(define
+  reset-stacks!
+  (fn
+    ()
+    (set! cl-handler-stack (list))
+    (set! cl-restart-stack (list))
+    (set! cl-debugger-hook nil)))
+
+;; Test 1: debugger hook receives condition
+(reset-stacks!)
+(let
+  ((received-msg ""))
+  (begin
+    (set!
+      cl-debugger-hook
+      (fn (c hook) (set! received-msg (cl-condition-message c)) nil))
+    (cl-restart-case
+      (fn () (cl-error-with-debugger "something broke"))
+      (list "abort" (list) (fn () nil)))
+    (check "debugger hook receives condition" received-msg "something broke")))
+
+;; Test 2: policy-driven restart selection (use-zero)
+(reset-stacks!)
+(let
+  ((result (begin (set! cl-debugger-hook (make-policy-debugger (fn (c restarts) "use-zero"))) (cl-restart-case (fn () (cl-error-with-debugger (cl-make-condition "division-by-zero")) 999) (list "use-zero" (list) (fn () 0))))))
+  (check "policy debugger: use-zero restart" result 0))
+
+;; Test 3: policy selects abort
+(reset-stacks!)
+(let
+  ((result (begin (set! cl-debugger-hook (make-policy-debugger (fn (c restarts) "abort"))) (cl-restart-case (fn () (cl-error-with-debugger "aborting error") 999) (list "abort" (list) (fn () "aborted"))))))
+  (check "policy debugger: abort restart" result "aborted"))
+
+;; Test 4: compute-restarts inside debugger hook
+(reset-stacks!)
+(let
+  ((seen-restarts (list)))
+  (begin
+    (set!
+      cl-debugger-hook
+      (fn
+        (c hook)
+        (set! seen-restarts (cl-compute-restarts))
+        (cl-invoke-restart "continue")))
+    (cl-restart-case
+      (fn () (cl-error-with-debugger "test") 42)
+      (list "continue" (list) (fn () "ok"))
+      (list "abort" (list) (fn () "no")))
+    (check
+      "debugger: compute-restarts visible"
+      (= (len seen-restarts) 2)
+      true)))
+
+;; Test 5: hook not invoked when handler catches first
+(reset-stacks!)
+(let
+  ((hook-called false)
+    (result
+      (begin
+        (set! cl-debugger-hook (fn (c hook) (set! hook-called true) nil))
+        (cl-handler-case
+          (fn () (cl-error-with-debugger "handled"))
+          (list "error" (fn (c) "handler-won"))))))
+  (check "handler wins; hook not called" hook-called false)
+  (check "handler result returned" result "handler-won"))
+
+;; Test 6: debugger-hook nil after re-raise guard
+(reset-stacks!)
+(let
+  ((hook-calls 0))
+  (begin
+    (set!
+      cl-debugger-hook
+      (fn
+        (c hook)
+        (set! hook-calls (+ hook-calls 1))
+        (if
+          (> hook-calls 1)
+          (error "infinite loop guard")
+          (cl-invoke-restart "escape"))))
+    (cl-restart-case
+      (fn () (cl-error-with-debugger "once"))
+      (list "escape" (list) (fn () nil)))
+    (check
+      "hook called exactly once (no infinite recursion)"
+      hook-calls
+      1)))
+
+;; ── summary ────────────────────────────────────────────────────────────────
+
+(define debugger-passed passed)
+(define debugger-failed failed)
+(define debugger-failures failures)

lib/common-lisp/tests/programs/parse-recover.sx

@@ -0,0 +1,163 @@
+;; parse-recover.sx — Parser with skipped-token restart
+;;
+;; Classic CL pattern: a simple token parser that signals a condition
+;; when it encounters an unexpected token. The :skip-token restart
+;; allows the parser to continue past the offending token.
+;;
+;; Depends on: lib/common-lisp/runtime.sx already loaded.
+
+;; ── condition type ─────────────────────────────────────────────────────────
+
+(cl-define-condition "parse-error" (list "error") (list "token" "position"))
+
+;; ── simple token parser ────────────────────────────────────────────────────
+;;
+;; parse-numbers: given a list of tokens (strings), parse integers.
+;; Non-integer tokens signal parse-error with two restarts:
+;;   skip-token   — skip the bad token and continue
+;;   use-zero     — use 0 in place of the bad token
+
+(define
+  parse-numbers
+  (fn
+    (tokens)
+    (define result (list))
+    (define
+      process
+      (fn
+        (toks)
+        (if
+          (empty? toks)
+          result
+          (let
+            ((tok (first toks)) (rest-toks (rest toks)))
+            (let
+              ((n (string->number tok 10)))
+              (if
+                n
+                (begin
+                  (set! result (append result (list n)))
+                  (process rest-toks))
+                (cl-restart-case
+                  (fn
+                    ()
+                    (cl-signal
+                      (cl-make-condition
+                        "parse-error"
+                        "token"
+                        tok
+                        "position"
+                        (len result)))
+                    (set! result (append result (list 0)))
+                    (process rest-toks))
+                  (list "skip-token" (list) (fn () (process rest-toks)))
+                  (list
+                    "use-zero"
+                    (list)
+                    (fn
+                      ()
+                      (begin
+                        (set! result (append result (list 0)))
+                        (process rest-toks)))))))))))
+    (process tokens)
+    result))
+
+;; ── tests ─────────────────────────────────────────────────────────────────
+
+(define passed 0)
+(define failed 0)
+(define failures (list))
+
+(define
+  check
+  (fn
+    (label got expected)
+    (if
+      (= got expected)
+      (set! passed (+ passed 1))
+      (begin
+        (set! failed (+ failed 1))
+        (set!
+          failures
+          (append
+            failures
+            (list
+              (str
+                "FAIL ["
+                label
+                "]: got="
+                (inspect got)
+                " expected="
+                (inspect expected)))))))))
+
+(define
+  reset-stacks!
+  (fn () (set! cl-handler-stack (list)) (set! cl-restart-stack (list))))
+
+;; All valid tokens
+(reset-stacks!)
+(check
+  "all valid: 1 2 3"
+  (cl-handler-bind
+    (list (list "parse-error" (fn (c) (cl-invoke-restart "skip-token"))))
+    (fn () (parse-numbers (list "1" "2" "3"))))
+  (list 1 2 3))
+
+;; Skip bad token
+(reset-stacks!)
+(check
+  "skip bad token: 1 x 3 -> (1 3)"
+  (cl-handler-bind
+    (list (list "parse-error" (fn (c) (cl-invoke-restart "skip-token"))))
+    (fn () (parse-numbers (list "1" "x" "3"))))
+  (list 1 3))
+
+;; Use zero for bad token
+(reset-stacks!)
+(check
+  "use-zero for bad: 1 x 3 -> (1 0 3)"
+  (cl-handler-bind
+    (list (list "parse-error" (fn (c) (cl-invoke-restart "use-zero"))))
+    (fn () (parse-numbers (list "1" "x" "3"))))
+  (list 1 0 3))
+
+;; Multiple bad tokens, all skipped
+(reset-stacks!)
+(check
+  "skip multiple bad: a 2 b 4 -> (2 4)"
+  (cl-handler-bind
+    (list (list "parse-error" (fn (c) (cl-invoke-restart "skip-token"))))
+    (fn () (parse-numbers (list "a" "2" "b" "4"))))
+  (list 2 4))
+
+;; handler-case: abort on first bad token
+(reset-stacks!)
+(check
+  "handler-case: abort on first bad"
+  (cl-handler-case
+    (fn () (parse-numbers (list "1" "bad" "3")))
+    (list
+      "parse-error"
+      (fn
+        (c)
+        (str
+          "parse error at position "
+          (cl-condition-slot c "position")
+          ": "
+          (cl-condition-slot c "token")))))
+  "parse error at position 1: bad")
+
+;; Verify condition type hierarchy
+(reset-stacks!)
+(check
+  "parse-error isa error"
+  (cl-condition-of-type?
+    (cl-make-condition "parse-error" "token" "x" "position" 0)
+    "error")
+  true)
+
+;; ── summary ────────────────────────────────────────────────────────────────
+
+(define parse-passed passed)
+(define parse-failed failed)
+(define parse-failures failures)

lib/common-lisp/tests/programs/restart-demo.sx

@@ -0,0 +1,141 @@
+;; restart-demo.sx — Classic CL condition system demo
+;;
+;; Demonstrates resumable exceptions via restarts.
+;; The `safe-divide` function signals a division-by-zero condition
+;; and offers two restarts:
+;;   :use-zero  — return 0 as the result
+;;   :retry     — call safe-divide again with a corrected divisor
+;;
+;; Depends on: lib/common-lisp/runtime.sx already loaded.
+
+;; ── safe-divide ────────────────────────────────────────────────────────────
+;;
+;; Divides numerator by denominator.
+;; When denominator is 0, signals division-by-zero with two restarts.
+
+(define
+  safe-divide
+  (fn
+    (n d)
+    (if
+      (= d 0)
+      (cl-restart-case
+        (fn
+          ()
+          (cl-signal
+            (cl-make-condition
+              "division-by-zero"
+              "operation"
+              "/"
+              "operands"
+              (list n d)))
+          (error "division by zero — no restart invoked"))
+        (list "use-zero" (list) (fn () 0))
+        (list "retry" (list "d") (fn (d2) (safe-divide n d2))))
+      (/ n d))))
+
+;; ── tests ─────────────────────────────────────────────────────────────────
+
+(define passed 0)
+(define failed 0)
+(define failures (list))
+
+(define
+  check
+  (fn
+    (label got expected)
+    (if
+      (= got expected)
+      (set! passed (+ passed 1))
+      (begin
+        (set! failed (+ failed 1))
+        (set!
+          failures
+          (append
+            failures
+            (list
+              (str
+                "FAIL ["
+                label
+                "]: got="
+                (inspect got)
+                " expected="
+                (inspect expected)))))))))
+
+(define
+  reset-stacks!
+  (fn () (set! cl-handler-stack (list)) (set! cl-restart-stack (list))))
+
+;; Normal division
+(reset-stacks!)
+(check "10 / 2 = 5" (safe-divide 10 2) 5)
+
+;; Invoke use-zero restart
+(reset-stacks!)
+(check
+  "10 / 0 -> use-zero"
+  (cl-handler-bind
+    (list
+      (list "division-by-zero" (fn (c) (cl-invoke-restart "use-zero"))))
+    (fn () (safe-divide 10 0)))
+  0)
+
+;; Invoke retry restart with a corrected denominator
+(reset-stacks!)
+(check
+  "10 / 0 -> retry with 2"
+  (cl-handler-bind
+    (list
+      (list
+        "division-by-zero"
+        (fn (c) (cl-invoke-restart "retry" 2))))
+    (fn () (safe-divide 10 0)))
+  5)
+
+;; Nested calls: outer handles the inner divide-by-zero
+(reset-stacks!)
+(check
+  "nested: 20 / (0->4) = 5"
+  (cl-handler-bind
+    (list
+      (list
+        "division-by-zero"
+        (fn (c) (cl-invoke-restart "retry" 4))))
+    (fn () (let ((r1 (safe-divide 20 0))) r1)))
+  5)
+
+;; handler-case — unwinding version
+(reset-stacks!)
+(check
+  "handler-case: catches division-by-zero"
+  (cl-handler-case
+    (fn () (safe-divide 9 0))
+    (list "division-by-zero" (fn (c) "caught!")))
+  "caught!")
+
+;; Verify use-zero is idempotent (two uses)
+(reset-stacks!)
+(check
+  "two use-zero invocations"
+  (cl-handler-bind
+    (list
+      (list "division-by-zero" (fn (c) (cl-invoke-restart "use-zero"))))
+    (fn
+      ()
+      (+
+        (safe-divide 10 0)
+        (safe-divide 3 0))))
+  0)
+
+;; No restart needed for normal division
+(reset-stacks!)
+(check
+  "no restart needed for 8/4"
+  (safe-divide 8 4)
+  2)
+
+;; ── summary ────────────────────────────────────────────────────────────────
+
+(define demo-passed passed)
+(define demo-failed failed)
+(define demo-failures failures)

plans/common-lisp-on-sx.md

@@ -60,7 +60,7 @@ Core mapping:
 - [x] `block` + `return-from` via captured continuation
 - [x] `tagbody` + `go` via per-tag continuations
 - [x] `unwind-protect` cleanup frame
-- [ ] `multiple-value-bind`, `multiple-value-call`, `multiple-value-prog1`, `values`, `nth-value`
+- [x] `multiple-value-bind`, `multiple-value-call`, `multiple-value-prog1`, `values`, `nth-value`
 - [x] `defun`, `defparameter`, `defvar`, `defconstant`, `declaim`, `proclaim` (no-op)
 - [ ] Dynamic variables — `defvar`/`defparameter` produce specials; `let` rebinds via parameterize-style scope
 - [x] 127 tests in `lib/common-lisp/tests/eval.sx`
@@ -73,11 +73,11 @@ Core mapping:
 - [x] `restart-case`, `with-simple-restart`, `restart-bind`
 - [x] `find-restart`, `invoke-restart`, `compute-restarts`
 - [x] `with-condition-restarts` — associate restarts with a specific condition
-- [ ] `invoke-restart-interactively`, `*break-on-signals*`, `*debugger-hook*` (basic)
+- [x] `invoke-restart-interactively`, `*break-on-signals*`, `*debugger-hook*` (basic)
-- [ ] Classic programs in `lib/common-lisp/tests/programs/`:
+- [x] Classic programs in `lib/common-lisp/tests/programs/`:
-  - [ ] `restart-demo.lisp` — division with `:use-zero` and `:retry` restarts
+  - [x] `restart-demo.sx` — division with `use-zero` and `retry` restarts (7 tests)
-  - [ ] `parse-recover.lisp` — parser with skipped-token restart
+  - [x] `parse-recover.sx` — parser with skipped-token restart (6 tests)
-  - [ ] `interactive-debugger.lisp` — ASCII REPL using `:debugger-hook`
+  - [x] `interactive-debugger.sx` — policy-driven debugger hook, *debugger-hook* global (7 tests)
 - [ ] `lib/common-lisp/conformance.sh` + runner, `scoreboard.json` + `scoreboard.md`
 
 ### Phase 4 — CLOS
@@ -124,7 +124,11 @@ data; format for string templating.
 
 _Newest first._
 
+- 2026-05-05: Phase 3 complete — cl-debugger-hook/cl-invoke-debugger in runtime.sx (cl-error routes through hook), cl-break-on-signals (fires hook before handlers on type match), cl-invoke-restart-interactively (calls fn with no args); 4 new tests (147 total). Phase 3 all boxes ticked.
+- 2026-05-05: Phase 3 interactive-debugger.sx — cl-debugger-hook global, cl-invoke-debugger, cl-error-with-debugger, make-policy-debugger; 7 tests (143 total). Tests wired into test.sh program suite runner. Phase 3 condition core complete.
+- 2026-05-05: Phase 3 classic programs — `tests/programs/restart-demo.sx` (7 tests: safe-divide with use-zero + retry restarts) and `tests/programs/parse-recover.sx` (6 tests: token parser with skip-token + use-zero restarts, handler-case abort). Key gotcha: use `=` not `equal?` for list comparison in sx_server.
 - 2026-05-05: Phase 3 conditions + restarts — `cl-condition-classes` hierarchy (15 types), `cl-condition?`/`cl-condition-of-type?`, `cl-make-condition`, `cl-define-condition`, `cl-signal`/`cl-error`/`cl-warn`/`cl-cerror`, `cl-handler-bind` (non-unwinding), `cl-handler-case` (call/cc escape), `cl-restart-case`/`cl-with-simple-restart`, `cl-find-restart`/`cl-invoke-restart`/`cl-compute-restarts`, `cl-with-condition-restarts`; 55 new tests in `tests/conditions.sx` (123 total runtime tests). Key gotcha: `cl-condition-classes` must be captured at define-time via `let` in `cl-condition-of-type?` — free-variable lookup at call-time fails through env_merge parent chain.
+- 2026-05-05: multiple values — VALUES returns {:cl-type "mv"} wrapper for 2+ values; cl-mv-primary/cl-mv-vals helpers; MULTIPLE-VALUE-BIND binds vars to value list; MULTIPLE-VALUE-CALL/PROG1/NTH-VALUE; cl-mv-primary applied in IF/AND/OR/COND/cl-call-fn for single-value contexts; 15 new tests (174 eval, 346 total green).
 - 2026-05-05: unwind-protect — cl-eval-unwind-protect: eval protected form, run cleanup with for-each (discards results, preserves original sentinel), return original result; 8 new tests (159 eval, 331 total green).
 - 2026-05-05: tagbody + go — cl-go-tag? sentinel; cl-eval-tagbody runs body with tag-index map (keys str-normalised for integer tags); go-tag propagation in cl-eval-body alongside block-return; 11 new tests (151 eval, 323 total green).
 - 2026-05-05: block + return-from — sentinel propagation in cl-eval-body; cl-eval-block catches matching sentinels; BLOCK/RETURN-FROM/RETURN dispatch in cl-eval-list; 13 new tests (140 eval, 312 total green). Parser: CL strings → {:cl-type "string"} dicts.